Machine vision devices with configurable illumination and aiming pattern generation

ABSTRACT

Machine vision devices with configurable illumination and aiming pattern generation are disclosed. An example system includes a housing having a cavity; an imaging sub-assembly mounted in the cavity including: an imager configured to capture an image; an aiming light source mounted in the housing configured to generate a collimated beam of light, an illumination light source configured to generate illumination light; and interchangeable first and second cover plates configured for mounting to the housing in front of the imaging sub-assembly to form an external cover for the housing and sealably protect the imager from an environment, wherein the first and second cover plates have respective passive optical elements that modify the collimated beam of light to form respective aiming patterns, and wherein at least one of the first cover plate or the second cover plate has a third optical element that modifies the illumination light.

BACKGROUND

Machine vision devices capture images within a given imaging field ofview (FOV). Illumination and aiming pattern need to match the imagingFOV. Therefore, illumination and aiming pattern generators are oftendifferent for different applications and often require differentindividual parts. Thus, usually multiple configurations of a machinevision device are stocked, for example, wide angle, midrange, and longrange. If a customer needs a different type of illumination and/oraiming pattern, they may need to replace the machine vision device, orreplace multiple optical components, which makes it difficult to(re-)configure the machine vision device. Therefore, it would bebeneficial to have an easy, quick way to (re-)configure illumination andaiming pattern with less labor and fewer steps to follow.

SUMMARY

In an embodiment, the present invention is a system including a housinghaving a cavity; an imaging sub-assembly mounted in the cavity, theimaging sub-assembly including: an imager configured to capture an imageof a portion of an environment in an imaging FOV; an aiming light sourcemounted in the housing configured to generate a collimated beam oflight, wherein the aiming light source is offset from the imagingsub-assembly; an illumination light source configured to generateillumination light; and interchangeable first and second cover platesconfigured for mounting to the housing in front of the imagingsub-assembly to form an external cover for the housing and sealablyprotect the imager from an environment, wherein the first and secondcover plates have respective first and second passive optical elementsthat modify the collimated beam of light to form respective first andsecond aiming patterns, and wherein at least one of the first coverplate or the second cover plate has a third optical element thatmodifies the illumination light.

In a variation of this embodiment, the imaging sub-assembly furtherincludes a lens group configurable to support first and second imagingFOVs, wherein the first cover plate, when mounted, supports the firstimaging FOV, and wherein the second cover plate, when mounted, supportsthe second imaging FOV.

In a variation of this embodiment, the imaging sub-assembly furtherincludes a lens group configurable to support first and second imagingFOVs, wherein the first passive optical element, when the first coverplate is mounted, forms a first aiming pattern in the first imaging FOV,and wherein the second passive optical element, when the second coverplate is mounted, forms a second aiming pattern in the second imagingFOV.

In a variation of this embodiment, the first and second cover plates areintegrally formed.

In a variation of this embodiment, the first cover plate is formed of asingle piece of optical grade plastic transparent for the light from thelight source to pass through, such as polycarbonate, acrylic, Zeonex,etc.

In a variation of this embodiment, the first passive optical elementincludes: one or more diffractive optical elements; and an optical wedgeconfigured to adjust an axis of the first aiming pattern relative to anaxis of the collimated beam of light, and wherein the first passiveoptical element is at least one of formed, molded or inset in the firstcover plate.

In a variation of this embodiment, the first passive optical element ispatterned to generate the first aiming pattern as structured light.

In a variation of this embodiment, the imaging sub-assembly furtherincludes a second illumination light source configured to generatesecond illumination light, wherein the first cover plate furtherincludes a fourth optical portion configured to direct at least some ofthe second illumination light into the imaging FOV.

In a variation of this embodiment, the aiming light source includes alaser diode and a collimating lens.

In a variation of this embodiment, the third optical element includes alens molded into the first cover plate to focus the illumination lightand direct the illumination light toward the imaging FOV.

In a variation of this embodiment, neither the first cover plate nor thesecond cover plate has an image modifying element.

In another embodiment, the present invention is an imaging systemcomprising: a housing; and an imaging sub-assembly mounted in thehousing, the imaging sub-assembly including: an imager to capture animage of a portion of an environment in a FOV; an aiming light sourcemounted in the housing configured to generate a collimated beam oflight, wherein the aiming light source is offset from the imagingsub-assembly; and an illumination light source configured to generateillumination light, wherein the housing is configured to receiveinterchangeable first and second cover plates for mounting to thehousing in front of the imaging sub-assembly to form an external coverfor the housing and sealably protect the imager from an environment,wherein the first and second cover plates have respective first andsecond passive optical elements that modify the collimated beam of lightto form respective aiming patterns, and wherein at least one of thefirst cover plate or the second cover plate has an optical element thatmodifies the illumination light.

In yet embodiment, the present invention is a method of assembling amachine vision device, the method comprising: providing an assemblyincluding: a housing having a cavity; an imaging sub-assembly in thecavity; an aiming light source in the cavity configured to generate acollimated beam of light, wherein the aiming light source is offset fromthe imaging sub-assembly; and an illumination light source; configuringthe imaging sub-assembly to capture an image of a portion of anenvironment in an imaging FOV; configuring the illumination light sourceto generate illumination light; and selecting one of interchangeablefirst and second cover plates based at least on the configured imagingFOV; and mounting the selected one of the interchangeable first andsecond cover plates to the housing to form an external cover for thehousing and sealably protect the imaging sub-assembly from anenvironment, wherein the first and second cover plates have respectivefirst and second passive optical elements that modify the collimatedbeam of light to form respective first and second aiming patterns, andwherein at least one of the first cover plate or the second cover platehas an optical element that modifies the illumination light.

In a variation of this embodiment, the method further comprises:unmounting the selected one of the interchangeable first and secondcover plates from the housing; configuring the imaging sub-assembly tocapture an image of a portion of an environment in a different imagingFOV; and mounting the unselected one of interchangeable first and secondcover plates to the housing.

In a variation of this embodiment, neither of the first cover plate orthe second cover plate has an image modifying element.

In a variation of this embodiment, the imaging sub-assembly includes alens group configurable to support first and second imaging FOVs,wherein the first passive optical element, when the first cover plate ismounted, forms a first aiming pattern in the first imaging FOV, andwherein the second passive optical element, when the second cover plateis mounted, forms a second aiming pattern in the second imaging FOV.

In a variation of this embodiment, the first and second cover plates areintegrally formed.

In a variation of this embodiment, the first passive optical elementincludes: one or more diffractive optical elements; and an optical wedgeconfigured to adjust an axis of an aiming pattern relative to an axis ofthe collimated beam of light, and wherein the first passive opticalelement is at least one of formed, molded, or inset in the first coverplate.

In a variation of this embodiment, the aiming light source includes alaser diode and a collimating lens.

In a variation of this embodiment, the third optical element includes alens and/or a wedge molded into for formed in the first cover plate tofocus the illumination light and direct the illumination light towardthe imaging FOV.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures, where like reference numerals refer toidentical or functionally similar elements throughout the separateviews, together with the detailed description below, are incorporated inand form part of the specification, and serve to further illustrateembodiments of concepts that include the claimed invention, and explainvarious principles and advantages of those embodiments.

FIG. 1 is an isometric view of an example machine vision device havingan interchangeable front cover plate in accordance with someembodiments.

FIG. 2 is a partially exploded view of the machine vision device of FIG.1.

FIG. 3 is a cross-sectional side view of the machine vision device ofFIG. 1.

FIG. 4 is an isometric view of the example front cover plate of FIGS.1-3.

FIG. 5 is a cross-sectional side view of the machine vision device ofFIG. 1 with a different interchangeable front cover plate installed.

FIG. 6 is an isometric view of the example front cover plate of FIG. 5.

FIG. 7 illustrates an example illuminated aiming pattern that may begenerated by the example machine vision devices of FIGS. 1-3 and 5.

Skilled artisans will appreciate that elements in the figures areillustrated for simplicity and clarity and have not necessarily beendrawn to scale. For example, the dimensions of some of the elements inthe figures may be exaggerated relative to other elements to help toimprove understanding of embodiments of the present invention.

The apparatus and method components have been represented whereappropriate by conventional symbols in the drawings, showing only thosespecific details that are pertinent to understanding the embodiments ofthe present invention so as not to obscure the disclosure with detailsthat will be readily apparent to those of ordinary skill in the arthaving the benefit of the description herein.

DETAILED DESCRIPTION

Machine vision devices having user- and/or field-replaceableinterchangeable front cover plates are disclosed herein. Disclosed frontcover plates are easily installed, integral pieces that include passiveoptical elements to simultaneously modify illumination and/or aiminglight generated by a machine vision device to correspond to an intendeduse and/or application. For example, if a machine vision device is to beconfigured and used for machine vision with an imaging FOV of 30degrees, then a front cover plate that generates an aiming pattern witha 30 degree spread and a corresponding illumination pattern may beinstalled and used. However, the same machine vision device can be usedto, for example, read direct product markings (DPMs) by reconfiguringthe machine vision device for a close focus distance, and installing adifferent front cover plate that generates an illuminated aiming patternfrom the aiming light generated by the machine vision device using adiffuser with a small hole for an aiming dot to pass through. Disclosedfront cover plates, when installed, additionally form an externalprotective cover for a machine vision device and sealably protect animager of the machine vision device from an environment. In someexamples, angles of the aiming pattern and/or the illumination patternare modified to center them within an imaging FOV at a predetermineddistance from the system. Because the front cover plates are integralpieces, they enable a machine vision device to be easily adapted to anintended use without having to manipulate and/or install multiple smalloptical pieces. Thus, a single model of machine vision device can beadapted for multiple intended uses through software configuration andthe simple installation of a corresponding front plate cover. As usedherein, being integral means that a front cover plate is installedand/or removed as a single piece even if multiple pieces (e.g., lenses,lenslets, wedges, diffractive optical elements (DOEs), etc.) wereoriginally combined, at manufacturing, to form the single piece. Aftermanufacturing, the front cover plates disclosed herein are intended tobe used as single pieces and are not intended to be disassembled, evenif possible, into their constituent parts.

FIGS. 1-3 illustrate a first example machine vision device 100 having anexample camera assembly 101 and a first example interchangeable frontcover plate 102. FIG. 4 is an isometric view of the example front coverplate 102 of FIGS. 1-3. FIG. 5 illustrates a second example machinevision device 500 having the same camera assembly 101 and a second,different example interchangeable front cover plate 502. FIG. 6 is anisometric view of the example front cover plate of FIG. 5. As is clearlyshown in FIGS. 1 and 2, the front cover plates 102, 502 may be assembledto the camera assembly 101 with a plurality of screws to enable easyinstallation and easy uninstallation.

The camera assembly 101 includes a housing 104, and an imagingsub-assembly 106 disposed within a cavity 108 in the housing 104. Theimaging sub-assembly 106 includes an image sensor 110, and a lens group112 that allows for images of objects to be formed on the image sensor110.

The machine vision device 100 may be adapted to be inserted into adocking station, etc. (not shown) which, in some examples, may include apower source to provide power for the machine vision device 100. Themachine vision device 100 may further include an onboard power supply(not shown) such as a battery, and a printed circuit board (PCB) 114which may accommodate a memory and a controller that controls operationof the machine vision device 100. The machine vision device 100 mayinclude any number of additional components such as decoding systems,processors, and/or circuitry coupled to the PCB 114 to assist inoperation of the machine vision device 100.

In an embodiment, the image sensor 110 is a solid-state device, forexample, a CCD or a CMOS imager, having a one-dimensional array ofaddressable image sensors or pixels arranged in a single row, or atwo-dimensional array of addressable image sensors or pixels arranged inmutually orthogonal rows and columns, and operative for detecting returnlight captured by the lens group 112 over an imaging FOV along animaging axis that is normal to the substantially flat image sensor 110through an imaging portion or zone 115 of the window cover plate 102.The return light is scattered and/or reflected from a target over theFOV. In some embodiments, the imaging axis is coaxial with a centralaxis of the lens group 112. The lens group 112 is operative for focusingthe return light onto the array of image sensors to enable the target tobe read. In particular, the light that impinges on the pixels is sensedand the output of those pixels produce image data that is associatedwith the environment that appears within the FOV (which can include thetarget). This image data may be processed by a controller (e.g., bybeing sent to a decoder) which identifies and decodes decodable indiciacaptured in the image data. Once the decode is performed successfully,the reader can signal a successful “read” of the target (e.g., abarcode).

The lens group 112 may also be fixedly mounted relative to the housing104 using any number of components and/or approaches. The lens group 112is configurable to focus at different distances and/or to image overdifferent fields of view (FOVs). For example, with a FOV of 30 degrees,a FOV of 46 degrees, at far distances, at close distances (e.g., on aDPM), etc.

In the illustrated example, the housing 104 includes an illuminationsystem configured to illuminate a target object for imaging. Theillumination system may include an illumination PCB 116 and one or moreillumination light sources, four of which are designated at referencenumerals 118-121. Example illumination light sources 118-121 includelight emitting diodes, laser diodes, black body radiation sources, oranother illumination light sources mounted to the illumination PCB 116.The front cover plate 102 may include one or more passive opticalelements (e.g., lenses, wedges, etc.) for respective ones of theillumination light sources 118-121 that will be used (i.e., turned on)for a particular application for dispersing or focusing opticalradiation for illumination of a target object. For example, in theexample configuration of FIG. 3, the illumination light source 118 isdisabled, the illumination light source 119 is enabled, and the frontcover plate 102 includes an in-molded lens 122 to focus the illuminationlight emitted by the illumination light source 120 on to a target. Inthe example configuration of FIG. 5, the portion of the front coverplate 502 associated with the illumination light source 120 is left isoptically blank to allow the diffuse illumination light 504 generated bythe illumination light source 120 to diffusely illuminate the imagingFOV 506.

In the illustrated example, the housing 104 includes an aiming patterngenerator 124 configured to generate an illuminated aiming pattern, suchas an example pattern 700 shown in FIG. 7. To generate aiming light, theaiming pattern generator 124 includes an aiming light source 128. Anexample aiming light source 128 is as a collimated beam source having alaser diode and collimating lens to generate a collimated beam of light.To modify the aiming light generated by the aiming light source 128 toform the illuminated aiming pattern 126, the front cover plate 102 mayinclude one or more passive optical elements 130, such as a pattern ofone or more DOEs (e.g., beam splitters, pattern generators, beamshapers, gratings, etc.) or other beam shaping elements. The front coverplate 102 may also include an optical wedge to tilt the illuminatedaiming pattern 126, i.e., to tilt a propagation axis thereof, such thatthe aiming pattern 126 falls in the imaging FOV at a particulardistance. The optical wedge may be formed into an entrance side of thefront cover plate 102, an exit side of the front cover plate 102, or bya combination of alterations to both. The DOE may be formed on eitherthe entrance side or the exit side and may be formed on an opposite sideof the optical wedge, in some examples.

In another example, the portion of a front cover plate corresponding tothe aiming light source 128 is patterned to form a known pattern oflight that may be projected onto a surface. When a machine vision devicehaving the front cover plate views the pattern from one (or more)different perspectives, the surface features of a target distort thepattern. The direction and size of the pattern distortions may be usedto reconstruct the surface topography of the target object, therebyenabling a device, system, etc. including the machine vision device toextract three dimensional (3D) information. In another example, theportion of a front cover plate corresponding to the aiming light source128 is patterned to correspond to a customer's logo so that thecustomer's logo is an aiming pattern.

While examples disclosed herein are described with reference to changinga front cover plate to adapt a machine vision device, camera, etc. fordifferent applications, uses, etc., it should be obvious that otherimaging devices (e.g., handheld, gun-style barcode readers) may besimilarly adapted for different applications, uses, etc. by changing afront window, etc. having portions that affect illumination light andaiming light.

In the foregoing specification, specific embodiments have beendescribed. However, one of ordinary skill in the art appreciates thatvarious modifications and changes can be made without departing from thescope of the invention as set forth in the claims below. Accordingly,the specification and figures are to be regarded in an illustrativerather than a restrictive sense, and all such modifications are intendedto be included within the scope of present teachings. Additionally, thedescribed embodiments/examples/implementations should not be interpretedas mutually exclusive, and should instead be understood as potentiallycombinable if such combinations are permissive in any way. In otherwords, any feature disclosed in any of the aforementionedembodiments/examples/implementations may be included in any of the otheraforementioned embodiments/examples/implementations.

The benefits, advantages, solutions to problems, and any element(s) thatmay cause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeatures or elements of any or all the claims. The claimed invention isdefined solely by the appended claims including any amendments madeduring the pendency of this application and all equivalents of thoseclaims as issued.

Moreover in this document, relational terms such as first and second,top and bottom, and the like may be used solely to distinguish oneentity or action from another entity or action without necessarilyrequiring or implying any actual such relationship or order between suchentities or actions. The terms “comprises,” “comprising,” “has”,“having,” “includes”, “including,” “contains”, “containing” or any othervariation thereof, are intended to cover a non-exclusive inclusion, suchthat a process, method, article, or apparatus that comprises, has,includes, contains a list of elements does not include only thoseelements but may include other elements not expressly listed or inherentto such process, method, article, or apparatus. An element proceeded by“comprises . . . a”, “has . . . a”, “includes . . . a”, “contains . . .a” does not, without more constraints, preclude the existence ofadditional identical elements in the process, method, article, orapparatus that comprises, has, includes, contains the element. The terms“a” and “an” are defined as one or more unless explicitly statedotherwise herein. The terms “substantially”, “essentially”,“approximately”, “about” or any other version thereof, are defined asbeing close to as understood by one of ordinary skill in the art, and inone non-limiting embodiment the term is defined to be within 10%, inanother embodiment within 5%, in another embodiment within 1% and inanother embodiment within 0.5%. The term “coupled” as used herein isdefined as connected, although not necessarily directly and notnecessarily mechanically. A device or structure that is “configured” ina certain way is configured in at least that way, but may also beconfigured in ways that are not listed.

The Abstract of the Disclosure is provided to allow the reader toquickly ascertain the nature of the technical disclosure. It issubmitted with the understanding that it will not be used to interpretor limit the scope or meaning of the claims. In addition, in theforegoing Detailed Description, it can be seen that various features aregrouped together in various embodiments for the purpose of streamliningthe disclosure. This method of disclosure is not to be interpreted asreflecting an intention that the claimed embodiments require morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive subject matter may lie in less thanall features of a single disclosed embodiment. Thus, the followingclaims are hereby incorporated into the Detailed Description, with eachclaim standing on its own as a separately claimed subject matter.

The invention claimed is:
 1. A system comprising: a housing having acavity; an imaging sub-assembly mounted in the cavity, the imagingsub-assembly including: an imager configured to capture an image of aportion of an environment in an imaging field of view (FOV); an aiminglight source mounted in the housing configured to generate a collimatedbeam of light, wherein the aiming light source is offset from theimaging sub-assembly; an illumination light source configured togenerate illumination light; and interchangeable first and second coverplates configured for mounting to the housing in front of the imagingsub-assembly to form an external cover for the housing and sealablyprotect the imager from an environment, wherein the first and secondcover plates have respective first and second passive optical elementsthat modify the collimated beam of light to form respective first andsecond aiming patterns, and wherein at least one of the first coverplate or the second cover plate has a third optical element thatmodifies the illumination light.
 2. The system of claim 1, wherein theimaging sub-assembly further includes a lens group configurable tosupport first and second imaging FOVs, wherein the first cover plate,when mounted, supports the first imaging FOV, and wherein the secondcover plate, when mounted, supports the second imaging FOV.
 3. Thesystem of claim 1, wherein the imaging sub-assembly further includes alens group configurable to support first and second imaging FOVs,wherein the first passive optical element, when the first cover plate ismounted, forms a first aiming pattern in the first imaging FOV, andwherein the second passive optical element, when the second cover plateis mounted, forms a second aiming pattern in the second imaging FOV. 4.The system of claim 1, wherein the first and second cover plates areintegrally formed.
 5. The system of claim 1, wherein the first coverplate is formed of a single piece of optical grade plastic.
 6. Thesystem of claim 1, wherein the first passive optical element includes:one or more diffractive optical elements; and an optical wedgeconfigured to adjust an axis of the first aiming pattern relative to anaxis of the collimated beam of light, and wherein the first passiveoptical element is at least one of formed, molded or inset in the firstcover plate.
 7. The system of claim 1, wherein the first passive opticalelement is patterned to generate the first aiming pattern as structuredlight.
 8. The system of claim 1, wherein the imaging sub-assemblyfurther includes a second illumination light source configured togenerate second illumination light, wherein the first cover platefurther includes a fourth optical portion configured to direct at leastsome of the second illumination light into the imaging FOV.
 9. Thesystem of claim 1, wherein the aiming light source includes a laserdiode and a collimating lens.
 10. The system of claim 1, wherein thethird optical element includes a lens molded into the first cover plateto focus the illumination light and direct the illumination light towardthe imaging FOV.
 11. The system of claim 1, wherein neither the firstcover plate nor the second cover plate has an image modifying element.12. A method of assembling a machine vision device, the methodcomprising: providing an assembly including: a housing having a cavity;an imaging sub-assembly in the cavity; an aiming light source in thecavity configured to generate a collimated beam of light, wherein theaiming light source is offset from the imaging sub-assembly; and anillumination light source; configuring the imaging sub-assembly tocapture an image of a portion of an environment in an imaging field ofview (FOV); configuring the illumination light source to generateillumination light; and selecting one of interchangeable first andsecond cover plates based at least on the configured imaging FOV; andmounting the selected one of the interchangeable first and second coverplates to the housing to form an external cover for the housing andsealably protect the imaging sub-assembly from an environment, whereinthe first and second cover plates have respective first and secondpassive optical elements that modify the collimated beam of light toform respective first and second aiming patterns, and wherein at leastone of the first cover plate or the second cover plate has an opticalelement that modifies the illumination light.
 13. The method of claim12, further comprising: unmounting the selected one of theinterchangeable first and second cover plates from the housing;configuring the imaging sub-assembly to capture an image of a portion ofan environment in a different imaging FOV; and mounting the unselectedone of interchangeable first and second cover plates to the housing. 14.The method of claim 12, wherein neither of the first cover plate or thesecond cover plate has an image modifying element.
 15. The method ofclaim 12, wherein the imaging sub-assembly includes a lens groupconfigurable to support first and second imaging FOVs, wherein the firstpassive optical element, when the first cover plate is mounted, forms afirst aiming pattern in the first imaging FOV, and wherein the secondpassive optical element, when the second cover plate is mounted, forms asecond aiming pattern in the second imaging FOV.
 16. The method of claim12, wherein the first and second cover plates are integrally formed. 17.The method of claim 12, wherein the first passive optical elementincludes: one or more diffractive optical elements; and an optical wedgeconfigured to adjust an axis of an aiming pattern relative to an axis ofthe collimated beam of light, and wherein the first passive opticalelement is at least one of formed, molded, or inset in the first coverplate.
 18. The method of claim 12, wherein the aiming light sourceincludes a laser diode and a collimating lens.
 19. The method of claim12, wherein the third optical element includes a lens molded into thefirst cover plate to focus the illumination light and direct theillumination light toward the imaging FOV.